Low Nwp Aqueous Polyurethane Composition

摘要

An aqueous composition with a sediment content <=5%, comprising a polyurethane dispersion wherein the polyurethane has an acid value in the range of from 25 to 65 mgKOH/g and comprises (i) 36 to 60 wt % of at least one aromatic polyisocyanate and where the polyurethane is prepared in the presence of (a) <=5 wt % of 1-methyl-2-pyrrolidinone by weight of the polyurethane, (b) 5 to 100 wt % of 1-ethyl-2-pyrrolidinone by weight of polyurethane and (c) water.